20857437 has 6 divisors (see below), whose sum is σ = 30127422. Its totient is φ = 13904952.

The previous prime is 20857429. The next prime is 20857469. The reversal of 20857437 is 73475802.

It can be written as a sum of positive squares in only one way, i.e., 17089956 + 3767481 = 4134^2 + 1941^2 .

It is not a de Polignac number, because 20857437 - 2³ = 20857429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20850437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1158738 + ... + 1158755.

It is an arithmetic number, because the mean of its divisors is an integer number (5021237).

Almost surely, 2^20857437 is an apocalyptic number.

It is an amenable number.

20857437 is a deficient number, since it is larger than the sum of its proper divisors (9269985).

20857437 is a wasteful number, since it uses less digits than its factorization.

20857437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2317499 (or 2317496 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 36.

The square root of 20857437 is about 4566.9943069813. The cubic root of 20857437 is about 275.2666812472.

The spelling of 20857437 in words is "twenty million, eight hundred fifty-seven thousand, four hundred thirty-seven".